Tidal Power & Coastal Communities: What It Means Outdoors

The Engineer Who Swam a Highland River to Understand the Tide

There is a story in a recent BBC News piece about a man called David Mummery that I keep coming back to. He is a mechanical engineer from Guildford who, sometime in the early 2010s, tied a cord across a fast-flowing Highland river, swam out into the current, gripped the rope, and let the water rush over him. He was not doing it for the experience, though I suspect the experience was extraordinary. He was doing it to feel what a turbine would feel. "As an engineer we do the maths and stuff," he told the BBC, "but sometimes you can get a lot more from actually touching the water and feeling it." That sentence is worth sitting with. It is the reason I wanted to write about this story.

The best understanding of water comes from being in it, and a Scottish tidal energy project is proving that the people who live and work on the coast already know this better than anyone.

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What Mummery Actually Built, and Why the Scale Matters

Scotland already has some of the most impressive tidal infrastructure on the planet. Nova Innovation deployed the world's first tidal stream array in Bluemull Sound, Shetland, in 2016. MeyGen runs four 1.5MW turbines on the seabed of the Pentland Firth. Orbital's O2 floating turbine, anchored at Fall of Warness in Orkney, generates 2MW. These are extraordinary machines. They are also enormous, expensive, and entirely dependent on mainland corporations, specialist vessels, and capital that most coastal communities will never see.

Mummery's Swimmer Turbine is none of those things. It is fiberglass and steel. It arrives in a shipping container. The assembly process, as he described it to the BBC, is closer to flat-pack furniture than to industrial marine engineering. Twenty components, a set of instructions, and a tractor on a slipway. The fishermen on Islay built it themselves. That is the point. Not 50kW as a number, but 50kW as something a community owns, maintains, and benefits from directly.

For those of us who spend time on the Scottish coast, on Islay or Luing or in the waters of the Firth of Lorn, this matters beyond energy policy. It is a statement about who understands coastal environments and who gets to act on that understanding.

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The Outdoor Angle: Tidal Waters as Living Infrastructure

Wild swimmers, sea kayakers, surfers and divers already know something that utility-scale energy developers are only beginning to formalise: tidal waters are not empty space. They are dynamic, readable, and deeply local. The same tidal race that makes Strangford Narrows one of the fastest-flowing stretches of water in the British Isles, where Mummery ran his 2020 proof-of-concept tests, is the same water that local mariners have been reading for generations. When he described pulling off "a full-scale tidal turbine installation out of a container deposited in a farmyard" with the help of local mariners he had just met, he was not describing a triumph of engineering. He was describing what happens when you respect the knowledge that already exists in a place.

That is a lesson the outdoor community has always understood intuitively. The best sea kayakers I know do not learn tidal races from charts alone. They ask the fishermen. They watch the kelp. They feel the eddy lines. Mummery swam a Highland river to feel the turbulence. That is the same instinct.

The practical consequence of projects like this, if they scale, is that tidal energy infrastructure becomes part of the coastal fabric rather than an imposition on it. Invisible below the surface, assembled by local hands, owned by local people. For anyone planning sea swims, paddles or dives around Scottish islands, that is a different relationship with the water than a 1.5MW utility turbine represents.

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The History of Marine Energy in Scotland: Brave Things That Take Decades

Mummery's own career is a useful lens here. Before founding Flex Marine Power in 2011, he worked on the Pelamis project in Orkney, a 180-metre wave energy machine nicknamed the sea snake, and the first deep-water floating wave device to generate power for the national grid. Pelamis went into administration in 2014. "The industry is littered with these examples of fantastic technologies and teams that do brave things that take decades," he told the BBC. "But at some point the market doesn't step up and they falter."

That is an honest assessment of a sector that has promised much and delivered inconsistently. The UK has genuinely exceptional tidal resources. Mummery himself describes the country as having "phenomenal waters for tidal power." But phenomenal resources and viable commercial technology are not the same thing, and the graveyard of marine energy prototypes is real.

What makes the Swimmer Turbine story feel different is the cost structure. Large tidal projects fail partly because the capital requirements are enormous and the returns are slow. A device that a fishing community can build, launch, and maintain from their own harbour has a fundamentally different economics. The £968,000 government grant that Flex Marine Power secured is a fraction of what MeyGen or Orbital required. That matters for longevity. Small, distributed, community-owned infrastructure is harder to kill than a single large installation dependent on one corporate backer.

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Islay: What the Island Already Knows

Islay is an interesting choice of test site, and not only because of its tidal resources. It is an island that has a long, functional relationship with its coastal environment. The whisky distilleries that the BBC mentions are not incidental local colour. They are evidence of an industrial culture that has sustained itself for centuries by understanding local conditions, water quality, peat, weather, and tidal access for supply boats. The people Mummery worked with at the boatyard were not passive recipients of mainland technology. They were, as he put it, "talented local people" who learned to assemble and launch the device themselves.

The moment he describes standing at the end of the slipway, watching local fishermen launch the turbine with their own tractor, without any of his team touching it, is the kind of thing that does not make it into energy policy documents but probably should. It is a proof of concept for community ownership as much as for the turbine itself.

For those planning to visit Islay for its wild coast, the sea kayaking around the Oa peninsula, or the diving around the many wrecks in the Sound of Islay, this is worth knowing. The island is not just a beautiful place to be outdoors. It is becoming a test case for what distributed coastal energy might look like at scale.

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What This Means for Your Body When You're Out There

Cold water, tidal currents, and long days on exposed coastline are physiologically demanding in ways that are easy to underestimate. The mental load of reading water, making route decisions in changeable conditions, and managing cold exposure over hours is real. It is not dramatic, but it accumulates. Anyone who has paddled a full day in the Hebrides or done a long sea swim in Scottish waters knows the particular kind of tired that settles in by late afternoon: not muscle failure, but something foggier.

Part of that is straightforward: cold water accelerates energy expenditure, and most people are underfuelling for the conditions they are actually in. But part of it is the cognitive and physiological cost of sustained outdoor effort, which is where daily nutrition becomes relevant rather than optional.

Rōnin includes ashwagandha at 600mg root extract and rhodiola rosea at 350mg root extract, both of which may support the body's response to sustained physical and mental demand. It also includes L-theanine at 200mg, which some evidence suggests may support calm focus under pressure, relevant when you are making real-time decisions in moving water. [GB-NHC] Vitamin B12 contributes to the reduction of tiredness and fatigue (Rōnin delivers 500µg as methylcobalamin), and [GB-NHC] magnesium contributes to a reduction of tiredness and fatigue (Rōnin delivers 1300mg magnesium malate). These are not dramatic claims. They are the baseline of being adequately nourished for the environment you are actually in. If you spend serious time on the coast, that baseline is worth attending to. More on the evidence behind stress and fatigue support at sea is at stress supplement uk natural.

There is also the sleep question. Long outdoor days in Scottish light, particularly in summer but also in the unpredictable shoulder seasons, can disrupt sleep architecture in ways people do not always connect to their performance the following day. If you are curious about the cortisol side of that, the piece on sleep cortisol and why youre wired at 11pm is worth reading. And if you want a broader look at the evidence for managing stress during high-output outdoor periods, best supplements for stress anxiety uk covers the research honestly. Find Rōnin at kojo.life.

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In Practice: Planning Around Tidal Energy Sites

If you are heading to any of the locations mentioned in the BBC report, here is what is practically worth knowing.

Strangford Narrows, County Down. This is one of the fastest tidal flows in the British Isles, up to 8 knots at peak spring tide. It is a serious sea kayaking location and a well-known dive site, but it demands genuine tidal planning. The narrows run between Portaferry and Strangford village. If you are paddling or diving here, use the UKHO tidal diamond data and cross-reference with local knowledge. The water does not forgive poor timing. Mummery's test equipment was tethered to a boat here; the forces involved are not theoretical.

Luing and the Firth of Lorn. The island of Luing, where Mummery ran his 2015 prototype trial, sits in a stretch of water with strong tidal races, particularly the Grey Dogs between Luing and Scarba, and the Corryvreckan whirlpool to the north. Corryvreckan is not a place to paddle without experience and local advice. The Grey Dogs are manageable at slack water and genuinely hazardous at peak flow. If you are sea kayaking the Slate Islands, time your passages carefully. The Met Office marine forecasts are the starting point, but tidal timing is separate from weather.

Islay. The tidal races around the Oa and through the Sound of Islay are strong but generally more forgiving than Corryvreckan. The island is genuinely excellent for coastal walking, sea swimming, and kayaking. The ferry from Kennacraig runs regularly. If you are planning a multi-day paddle around the island, the boatyards at Port Ellen and Port Askaig are the practical logistics bases. Wild camping is legal under Scottish access law, and the coast is largely uninhabited outside the villages.

Kit note. In all of these locations, a tow float for sea swimming, a VHF radio for paddling, and a dry suit rather than a wetsuit for anything beyond summer months are not optional extras. Scottish coastal water temperatures sit between 8°C and 14°C for most of the year. Cold water incapacitation is fast and unannounced. The UK government's coastal safety guidance is a reasonable starting point, but local knowledge from harbour masters and sea kayak guides is more useful in practice.

My Honest Take

I am not an energy journalist. I am not going to tell you whether the Swimmer Turbine will succeed commercially where Pelamis did not. Mummery is honest about that uncertainty himself. The marine energy sector has a long history of promising technologies that ran out of runway before the market caught up.

What I find genuinely compelling about this story, as reported by BBC News, is the method. A man tied himself to a rope in a Highland river to feel what his turbine would feel. He chose a shed in a Greenock shipyard over a glass office in Glasgow because the shed was on the quayside. He drove a shipping container to a Northern Ireland farmyard and assembled a full-scale tidal turbine with people he had just met. That is a particular kind of intelligence, one that respects the environment and the people who live in it, rather than arriving with a solution and looking for somewhere to put it.

The outdoor community runs on exactly that instinct. You do not learn a tidal race from a chart. You learn it from being in the water, from asking the people who fish it, from watching the kelp move. Mummery swam a river to understand a turbine. That is the right way to start.

FAQ: Tidal energy and the outdoor coast

Is tidal energy infrastructure a hazard for sea swimmers and kayakers?

The Swimmer Turbine sits entirely below the water surface and is invisible from above, according to the BBC report. Mummery specifically describes it as generating electricity "absolutely hidden" below the surface. For sea swimmers and kayakers, the practical risk is not the device itself but the tidal races that make sites like Strangford and the Firth of Lorn attractive for energy generation. Those races exist regardless of the turbines. Tidal timing and local knowledge remain the relevant safety factors.

Where in the UK are the strongest tidal resources for outdoor water sports?

The same locations that attract tidal energy developers tend to be the most demanding for outdoor water users. The Pentland Firth, Strangford Narrows, the Corryvreckan area, the Alderney Race in the Channel, and the Severn Estuary all have exceptional tidal energy potential and all require serious tidal planning for any water activity. The overlap is not coincidental. Strong tidal flow is the variable that matters for both.

What does community-owned tidal power mean for remote coastal areas?

If the Swimmer Turbine model scales as Mummery hopes, it could mean reliable electricity for islands and coastal communities that currently depend on expensive diesel generation or long, vulnerable grid connections. For outdoor visitors, that means better-supplied harbours, more resilient infrastructure, and communities that are economically healthier. The plan for Islay, as reported by the BBC, is to generate electricity directly for the island using tidal arrays owned by different local groups in different parts of the coast.